Automatic telephone system



. Patented Nov. 26, 1 929 UNITED STATES PATENT- OFFICE THEODOR KORTHKUER, OF BERLIN-SPANDA'U, GERMANY, ASSIGNOB TO '6. LORENZ, .AKTIEN GESELLSCHAI'T, OF LORENZWEG, BERLIN-TEMPELHOF, GERMANY AUTOMATIC TELEPHONE SYSTEM Application filed February 16, 1928, Serial No. 254,812, and in Germany February 16, 1927.

This invention relates to automatic telephone systems and is more partlcularly 1ntended to interconnect two automatic exchanges, so that a subscriber to one automatic 5 exchange may be connectedto a distant exchange over a connecting trunk line and may thus directly call a subscriber belonging to such distant exchange. may be associated to each automat c ex- 1 change a distance ofiice which may be called by any subscriber and which byhand or automatically will execute the deslred con nection with another automatic. exchange. It is known for telephonic transmission lines to use so-called repeaters at the beg nning and at the end of the line. On the other hand, for calling a subscriber by means of a number of current impulses as is the case with the widely known step-by-step automatlc system, such repeaters are very llable to cause distortion of the current impulses. Special impulse repeaters are therefore provided. I

' One object of my invention consists to provide an apparatus which enables the calling impulses to be transmitted d rectly by an impulse repeater automatically operated in both directions without being disturbed by the repeaters and the telephonic 3o transmission.

Another obj ect of my invention is to make it possible by use of the same impulse repeater to send calling impulses 1n both directions without the use of any additional operation dependent on the direction an automatic call is to be effected. v

The invention is more clearly set forth by the following detailed description taken with reference to the accompanying drawings. It

will be understood, that I do not limit myself to the specific examples shown, but that my invention may be embodied inany kind of system without departing from the scope of the appended claims. v

Referring to the drawings in which similar reference characters represent like parts throughout.

Figure 1 is a wiring diagram for an automatic telephone exchange plant showing To this end, thereschematically the switching mechanism in accordance with my invention.

Figure 2 is a similar diagram to Figure 1 whlch without the use of an operator enables automatic connection to be carried out.

Referring to Figure 1, it is supposed a call to arrive from a connecting line a,?) of an automatic exchange lying at A. Thereby a-b w ll be put into circuit and a circuit containing two windings of a relay S be closed, energizing relay S which by means of 1ts contact 8 will close a circuit containing the winding of a further relaySH. The path of the current for the latter will then be as follows: earth, contact 8 relay SH,. resistance W, negative terminal of battery (not shown in the drawing for the sake of simplicity), whose positive terminal is supposed to be connected to earth. Relay SH is a slow acting relay and will therefore remain 1n its attracted position during the entire period of the calling impulse transmission.

. The relay SH by means of its contact sh closes the circuit of an indicating lamp AL,

whose path may be traced as follows: earth,

contact sh, contact .e calling lamp AL, minus pole of battery. The operator in the exchange after the calling lamp AL having been lighted will put the answering plug A.St of a free two way connecting cord into the connecting jack V.K., whereby a working contact k' of the latter will be closed and relay E energized. The current path for the latter may be traced as. follows: earth, jack, contact is, contact 8 of relay SH, relay E and 5 minus pole of battery. Contact 6 operated by relay E will open again the lamp circuit thus switching ofl the calling lamp AL.

' The operator will put the remaining plug (connecting plug V.K.) of the connecting o cord into a free connecting jack leading to the desired automatic exchange at B and after having disconnected her answering set, the connection will be completed, and the .calling subscriber at A may operate his transmitting dial and select directly over the trunk line a desired subscriber of the distant exchange without the use of the repeaterll' which otherwise would distort the selecting or calling current impulses, whereas for tele phonic transmission the repeater U is used exclusively. The impulse repeating operation will be as follows: During the sending of the impulses by the subscriber, the currentloop containing the windings of relay S is consecutively opened and closed thereby correspondingly operating relay S.

\Vith the first operation of the dial of the subscriber relay S will be opened and relay N be energized, for which the path of current is as follows: earth, contact 872., relay N, contact 8 resistance W, minus pole of battery.

Relay N is a slow acting relay e. g. a copper collar relay and therefore holds its contact.

n by virtue of its retardation effect until the end of the impulse transmission. Contact 11/ is short-circuiting the secondary windings of the repeater U, whereby distortions of the current impulses are avoided. Contact 8 operated by relay S is opened and closed in accontact a will remain closed by relay S and telephonic transmission may be carried out across the windings of the repeater U in the well known manner.

If a connection is to be made in the inverse sense, i. e. in the case the operator is connecting a subscriber to a free toll line, by inserting the connecting plu contact is will close the circuit containing the winding W of a change over relay. The current path will be as 01- lows: earth, jack contact is, contact 871. contact e relay winding W, minus pole of battery. Relay W will, thereby, switch over the repeater together with the impulse relay S selecting current impulse contact 8 and short-circuiting contact 47. by means of its contacts 10 -10 in such a Wa that the transmission of the current impu ses may now be carried out in the reverse or outgoing direction. The following operation is exactly the same as outlined above for impulse current transmission in the incoming direction, the incoming line and outgoing line merely being exchanged with respect to each other. The same switching means as provided in accordance with my invention may also be employed in a choke coil repeater system-in connection with blocking condenser, as is more particularly represented by the wiring diagram'of Figure 2. The sending out of the current impulses, in this case, is effected in that the relay N being in its working position during the impulse transmission is short circuiting, by means of its contacts n and n the choke-coil Dr and in that it is.simultaneously severing the outgoing line from the condensers c in order to avoid disturbances of-the corrent impulses.

The diagram of Figure 2 represents a switching diagram which is also adapted for an automatic connection of an exchange with an outgoing toll line. If, for instance, the repeater arrangement is engaged by a threewire connection line coming from an automatic exchange, the first action will be the energization of the relay W over the third or as it is called in technical. terminology over the c-line. The relay W, by means of its contacts 'w 'w will then change over the repeater arrangement in the (1-?) line and relay S will be actuated by the formation of the closed current path over a-b as described above. The remaining switching operations will then be the same as set forth with reference to the arrangement of Figure 1.

In case a call is coming in the reverse direction i. e. from the two wire toll line ab, relay S and responsive to it relay SH will become energized. Relay SH, by virtue of its contact sh will then open the c-line leading to the automatic exchange, so that a calling from this opposite side may not be effected. The remaining operations are the same as described hereinbefore.

What I claim to be secured by Letters Patent in the United States is 1. In a repeater device for relaying electrical impulses comprising a primary circuit for carrying impulses to be repeated, a secondary circuit co-operating therewith for producing repeated impulses, an incoming line and an outgoing line, connections between said incoming and outgoing lines with said-primary and said secondary circuits, and means to reverse the relation of said connections in accordance with the direction in which tralfic is initiated.

2. A repeater for relaying electrical impulses comprising a relay device, a winding for said device to carry currents to be repeated, contacts co-operating therewith to produce repeating impulses, an incoming line and an outgoing line, operating connections of said incoming and outgoing lines with said winding and said contacts respectively, and means including switching elements to reverse the relation of said winding and said contacts in respect to said incoming and outgoing lines dependent on the direction in which impulse signals are initiated over said lines.

3. A-repeater for relaying electrical impulses, com rising a relay device, an incoming line an an outgoing line, operative connections of said incoming and said outgoing lines with said winding and said contacts respectively, and means including switching elements operated dependent on the direction Y in which impulses are initiated over said lines to reverse automatically the relation of said winding and said contacts in respect to said incoming and outgoing lines. o

4. A repeater for relaying electrical calling impulses in automatic telephone exchanges, comprising a relay device, a winding for said device to carry impulses to be repeated, co-operating contacts for said winding to produce repeated impulses, subscriber line terminals, and means associated with said repeater for establishing a connection between a calling subscriber and a called subscriber across said repeater, and means including switching elements to reverse the relation of said repeater winding and said repeater contacts with said first means inaccordance with operating conditions dependent on the initiation of a call in a distinct direction.

5. In a repeating device comprising a voice current repeater primary and secondary windings for said repeater, a selecting impulse current repeater having a primary control circuit associated with said primary winding and co-operating repeating contacts associated with said secondary winding, means to establish a signalling connection between a calling subscriber and a called subscriber across said repeater, and means including switching elements to establish automatically a proper relationship between calling line and called line in respect to said primary and said secondary circuits dependent on the direction in which a call is initiated.

6. In a repeating device comprising a voice current repeater primary and secondary windings for said repeater, a selecting impulse current repeater having a primary control circuit associated with said primary winding and co-operating repeating contacts associated with said secondary winding,

means to establish a signalling connection between a calling subscriber and a called subscriber across said repeater, and means including switching elements to establish auto matically a proper relationship between the calling line and the called line in respect to said primary and said secondary circuits deendent on the direction in which a call is initiated, and means for blocking the circuits carrying voice currents from the circuits carrying current impulses.

In testimony whereof I have afiixedmy signature.

TH. KORTHKUER. 

